It is common for the prostate gland to become enlarged as a man ages. As a male matures, the prostate goes through two main periods of growth, first early in puberty, and then again at around age 25, when the growth begins, and continues on through life. One of the effects of this continued growth can be pressure on the urethra, the passage through which urine passes from the bladder and the penis.
The urethra is surrounded by the prostate for part of its length. Within the confines of the prostate, the urine flows through a passage having a generally triangular cross-section. As the prostate enlarges, the layer of tissue surrounding the prostate restricts the prostate from expanding outward, causing the prostate to constrict the urethral passage. The condition of an enlarged, non-cancerous prostate is called benign prostatic hyperplasia (BPH), or benign prostatic hypertrophy.
Though the prostate continues to grow during most of a man's life, BPH rarely causes symptoms before age 40, but more than half of men in their sixties and as many as 90 percent in their seventies and eighties have some symptoms of BPH. BPH can make it difficult to the bladder to completely empty, and is associated with other urinary system problems well known in the medical field.
Current Treatment
Men who have BPH with symptoms usually need some kind of treatment at some time. Although the need for treatment is not usually urgent, doctors generally advise treatment once the problems become bothersome or present a health risk.
The most commonly used treatments for BPH include drug therapy, minimally invasive mechanical treatment, and surgery.
Among the drugs approved for example, by the U.S. FDA, are Finasteride (Proscar), dutasteride (Avodart), terazosin (Hytrin), doxazosin (Cardura), tamsulosin (Flomax), and alfuzosin (Uroxatral). These drugs act by relaxing the smooth muscle of the prostate and bladder neck to improve urine flow and to reduce bladder outlet obstruction. Use of finasteride and doxazosin together has also been found to be more effective than using either drug.
Drug treatment may only be partially effective in some cases. Researchers have therefore developed a number of mechanical procedures that relieve BPH symptoms but are less invasive than conventional surgery. These include transurethral microwave thermotherapy (TUMT), which uses microwaves to heat and destroy portions of prostate tissue, transurethral needle ablation (TUNA), which employs low-level radio-frequency energy delivered through twin needles to burn away selected regions of the enlarged prostate, and water-induced thermotherapy, which uses heated water to destroy portions of prostate tissue. The use of ultrasound waves to destroy prostate tissue is also undergoing clinical trials in the United States.
Urethral stents have also been employed in some instances, with varying degrees of effectiveness, but also exhibit some drawbacks in some cases, known in the art. These include pain and/or irritation, frequent urination and/or incontinence, and difficulty in removal (which proves to be necessary in one-third of cases).
Surgical removal of part of the prostate, thereby reducing pressure against the urethra is often regarded as the best long-term solution for patients with BPH. Among the types of surgery commonly employed is transurethral surgery which requires no external incision. Such procedures include transurethral resection of the prostate (TURP), by which prostate tissue is removed, transurethral incision of the prostate (TUIP), by which the urethra is widened by making a few small cuts in the bladder neck where the urethra joins the bladder, and in the prostate gland itself, and laser induced prostate tissue removal.
In the few cases where transurethral surgical procedures are not indicated, open surgery, which requires an external incision, may be used.
WO/2010/106543 referred to above, provides mechanical alternatives and methods to current non-surgical treatments for BPH.
Of general interest may be Gross et al. U.S. patent publication 2010/0130815, which is concerned with implantation of devices to provide pre-operative urethral expansion.